EP 0919844 A1 19990602 - Four group zoom lens
Title (en)
Four group zoom lens
Title (de)
Zoomobjektiv mit vier Linsengruppen
Title (fr)
Objectif à focale variable à quatre goupes de lentilles
Publication
Application
Priority
JP 34586097 A 19971201
Abstract (en)
This description discloses a zoom lens having, in succession from the object side, a first lens (F) unit fixed during a focal length change and having positive refractive power, a second lens unit (V) moved along the optical axis thereof during the focal length change, a third lens unit (C) for correcting the fluctuation of the image plane resulting from the focal length change, and a fourth lens unit (R) fixed during the focal length change and having positive refractive power, the second lens unit having a lens subunit (Va) of negative refractive power and a lens subunit (Vb) of positive refractive power, the lens subunits being moved at different speeds during the focal length change, and the conditions of the lens being satisfied to thereby well correct the fluctuations of aberrations during the focal length change. <IMAGE>
IPC 1-7
IPC 8 full level
G02B 13/18 (2006.01); G02B 15/167 (2006.01); G02B 15/173 (2006.01)
CPC (source: EP US)
G02B 15/144113 (2019.07 - EP US)
Citation (search report)
- [A] US 5179472 A 19930112 - OHNO KAZUNORI [JP], et al
- [A] US 5675439 A 19971007 - NAKATSUJI MASAHIRO [JP]
- [A] US 5636060 A 19970603 - SUZUKI TAKESHI [JP] & JP H0713075 A 19950117 - NIKON CORP
- [A] PATENT ABSTRACTS OF JAPAN vol. 008, no. 183 (P - 296) 23 August 1984 (1984-08-23)
Designated contracting state (EPC)
DE ES FR GB IT NL
DOCDB simple family (publication)
EP 0919844 A1 19990602; EP 0919844 B1 20060322; DE 69833908 D1 20060511; DE 69833908 T2 20061019; ES 2256909 T3 20060716; JP 3927670 B2 20070613; JP H11160620 A 19990618; US 6084721 A 20000704
DOCDB simple family (application)
EP 98122744 A 19981130; DE 69833908 T 19981130; ES 98122744 T 19981130; JP 34586097 A 19971201; US 20179598 A 19981201